Various semiconductor devices make use of regions of porous semiconductor material. Porous semiconductors, e.g. porous silicon, may be created in semiconductor wafers, by electrochemical etching methods, for example. However, processing the wafers may be challenging. For example, the wafer edges of ultrathin wafers tend to be very fragile regions, which may not be able to withstand strong mechanical forces. Yield losses may be experienced due to breakage or leakages.